Mean objective measurements of CNR and mean qualitative image scores^a

kV	mAs	CTDIw	CNR				Image Quality Score
			15 mg I/mL		20 mg I/mL		15 mg I/mL		20 mg I/mL
			Original	Q08	Original	Q08	Original	Q08	Original	Q08
100	150	23.9	9.2 ± 0.6	11.6 ± 1.0	11.8 ± 0.9	16.1 ± 2.5	2.00 ± 0.7	2.58 ± 0.8	2.25 ± 0.8	2.92 ± 0.8
	200	31.8	10.9 ± 1.7	14.3 ± 2.8^b	13.8 ± 2.2	19.2 ± 3.6	2.17 ± 0.7	2.50 ± 1.0	3.17 ± 0.8	3.58 ± 0.7^b
	250	39.8	12.0 ± 2.1	16.1 ± 2.6^b	16.0 ± 1.0	21.8 ± 1.4^b	2.58 ± 0.7	3.00 ± 0.4^b	3.42 ± 0.5	3.92 ± 0.7^b
120	100	24.0	8.7 ± 1.4	11.3 ± 0.7	11.3 ± 1.1	14.9 ± 1.6	1.83 ± 0.7	2.40 ± 0.5	2.17 ± 0.9	2.42 ± 1.0
	150	36.0	10.2 ± 1.0	14.2 ± 1.4^b	14.8 ± 1.2	21.8 ± 1.8^b	2.33 ± 0.8	2.75 ± 0.6	2.83 ± 0.7	3.50 ± 0.5^b
	200	48.0	11.5 ± 2.0^c	18.4 ± 2.3^b	17.3 ± 1.7^c	22.7 ± 2.3^b	2.50 ± 1.1^c	3.08 ± 0.8^b	3.12 ± 0.7^c	3.83 ± 0.8^b
135	100	30.7	9.80 ± 1.6	13.3 ± 0.9	12.3 ± 1.9	16.5 ± 1.6	1.67 ± 0.7	2.00 ± 0.7	2.58 ± 1.0	3.00 ± 1.0

a Data are the mean ± SD.
b CTA with QDS were significantly superior to the standard CTA (120 kVp and 200 mAs) with a P value < .05 (Wilcoxon signed rank test).
c Standard CTA.